Testing Differences in Ultra High Performance All-Season Tires

Tires tested:
Goodyear Eagle RS-A High Performance All-Season 205/50R17
Avon Tech M550 A/S Ultra High Performance Summer 225/45R17
Bridgestone Potenza RE950 Ultra High Performance All-Season 225/45R17
Michelin Pilot XGT Z4 Ultra High Performance All-Season 225/45R17

Vehicles used:
2003 BMW 330Ci

The objective of today's Ultra High Performance All-Season tires category is well known to consumers & tire engineers alike - deliver sporty h&ling while still maintaining some ability to cope with light snow & slush. This means blending the sporty nature & "three season" capability of a dedicated summer performance tire with the ability to provide some light slush & snow traction like an all-season tire.

The challenge to the tire manufacturers becomes developing a tire that truly meets the needs of drivers selecting tires from this category, & finding a way to differentiate their new product from other existing options available in the market.

The Tire Rack team conducted a Real World Road Ride & Performance Track Drive to compare the ride & h&ling characteristics of three of the more recent releases in the Ultra High Performance All-Season category - the Avon Tech M550 A/S, Bridgestone Potenza RE950 (V-speed rated) & the Michelin Pilot XGT Z4 Ultra High Performance All-Season tires. The Tech M550 A/S is a new product that is designed around extensive consumer feedback, the Potenza RE950 offers a recent expansion of sizes with higher speed ratings, & the Pilot XGT Z4 which is the re-release of a successful product.

Our evaluation used 2003 BMW 330Ci coupes, with 225/45R17 tires mounted on 17x8" wheels. This is a common Plus Zero tire & wheel package for the 330Ci coupe, & a popular Plus One package for st&ard 3 Series BMWs. Our evaluation used new, full tread depth tires.

We also included a fourth, 2003 BMW 330Ci fitted with the Original Equipment 205/50R17 Goodyear Eagle RS-A High Performance All-Season tires mounted on factory 17x7" wheels. We have included this vehicle/tire combination in other tire evaluations, & have found it helpful to have an OE-equipped vehicle in the test to evaluate the impact of installing the other products.

Goodyear Eagle RS-A

The Goodyear Eagle RS-A is a High Performance All-Season tire produced with several speed ratings & in a wide variety of sizes. Its design is heavily influenced by its use as an Original Equipment tire by BMW, Volkswagen, General Motors, Chrysler & others. The Eagle RS-A features a subtle asymmetric tread design with larger tread elements in the outside shoulder intended to deliver more responsive h&ling, cornering, & steering. Smaller tread blocks on the inside shoulder combined with wide tread & lateral grooves are intended to enhance wet & snow traction.

Out on the road, the Eagle RS-A exhibited ride comfort & noise levels that were equal to or better than the other three tires. The light road h&ling evaluated on our test loop was not quite as crisp as the other three Ultra High Performance All-Season tires in this test, but still considered typical for a tire in the High Performance All-Season category.

On the track in the dry, the Eagle RS-A performed well, but was a bit outmatched by the other three wider, more performance-oriented tires in this test. Steering response was good, but as we have found in previous tests, the Eagle RS-A can exhibit some understeer if pressed too hard.

In wet conditions, the Eagle RS-A delivered performance appropriate for a tire in the High Performance All-Season category. Grip level was good, but it was just not able to keep up with the Bridgestone Potenza RE950.

Avon Tech M550 A/S

The Avon Tech M550 A/S is the Ultra High Performance All-Season tire member of AVON Tyres' family of Tech performance tires. The attractively priced Tech M550 A/S is designed to provide flexibility for the drivers of sports cars, sports coupes & performance sedans by providing year-round traction, predictable h&ling & control in dry & wet road conditions, as well as in light snow.

The Tech M550 A/S features a silica-enhanced all-season tread compound molded into a directional tread design that features large independent tread blocks to provide stability on dry roads while its grooves help pump water & slush through the tire's footprint to increase hydroplaning resistance & foul weather traction. Lateral grooves & multiple sipes in each tread block increase the number of biting edges to enhance wet road & light snow traction.

On the inside, the Tech M550 A/S features twin steel belts reinforced by spirally wrapped nylon, along with a carcass that s&wiches a hard sidewall filler between polyester cord plies to help resist distortion at high speeds & while cornering.

On the road, our team praised the blend of comfort & performance delivered by the Tech M550 A/S. Ride quality received good marks from our team, where they found tread & impact noise levels to be moderate. Road h&ling around curves & highway off-ramps felt sure-footed & responsive, but not quite as crisp as the Michelin XGT Z4.

Evaluating the traction & h&ling limits on our dry test track, the Tech M550 A/S performed well & with no surprises. While the overall grip felt like it was close to the Bridgestone & Michelin products, the Tech M550 A/S delivered somewhat softer steering response. The slower steering response simply required the driver to adjust the timing of inputs to initiate & negotiate corners. Overall lap time was just behind the Michelin Pilot XGT Z4 & Bridgestone Potenza RE950.

With the course wetted down by our sprinkler system & periodic rain showers, the Tech M550 A/S was able to generate an overall grip level (lateral g's) equal to the Bridgestone Potenza RE950. Wet h&ling was predictable & well balanced, & if the car did begin to slide it was easily brought back under control.

Bridgestone Potenza RE950

The Bridgestone Potenza RE950 is an Ultra High Performance All-Season tire that was developed to meet the needs of the drivers of sports cars, coupes & sedans by blending dry, wet & year-round traction, even in light snow. The Potenza RE950 is Bridgestone's first tire in America to feature UNI-T AQ II technology which uses advanced compound & construction features to enhance & preserve wet traction through the tire's life.

On the outside, the Potenza RE950 molds Bridgestone's unique second-generation dual layer tread compound into a directional tread design. The dual layer compound is designed to enhance wet grip from day one, & also counteract the negative effects of aging on wet traction as the tire wears. The tread design features large tread blocks for quick response & sporty h&ling with lateral grooves that help move water toward the sides of the tire to resist hydroplaning. A continuous center rib helps reduce noise while providing constant road contact to enhance straight-line stability. Internally, the Potenza RE950 features a Computer Optimized Component System which blends twin, high tensile, steel belts with spiral-wrapped, jointless belt edge strips to stabilize the tread area & enhance h&ling, high-speed capability & ride quality while minimizing weight.

On the road, the Potenza RE950 delivered a sporty blend of h&ling & comfort, appropriate for a tire in the Ultra High Performance All-Season category. Our team found the steering to be responsive, with overall h&ling rated just behind the Pilot XGT Z4. Tread noise was moderate, with several faint but distinct pitches heard at most speeds.

On the h&ling track in the dry, the Potenza RE950 performed well, falling just behind the first place Michelin Pilot XGT Z4. The Potenza RE950 was easy to drive at the limit, thanks to its predictable blend of responsiveness & good overall grip. While the h&ling was not quite as laser-sharp as the Pilot XGT Z4, the Potenza RE950 has performed well every time we've tested it.

Under wet track conditions, The Potenza RE950 showed why Bridgestone is known for delivering good wet weather traction. The Potenza RE950 was the easiest to drive of the tires in this evaluation, combining good grip levels with precise steering response, & posting the fastest average overall wet lap time of the test.

Michelin Pilot XGT Z4

After a brief hiatus, Michelin has reintroduced the popular Michelin Pilot XGT Z4, giving drivers of performance sports cars, coupes & sedans an economical Michelin tire option. The Pilot XGT Z4 retains its intent to deliver good ride traits & long wear with year-round traction, even in light snow.

On the outside, the Pilot XGT Z4 tires feature a weather-tuned, Advanced Technology tread compound (formulated to balance dry grip, wet traction, light snow traction, & tread wear) molded into a directional tread design to provide h&ling in nearly every weather condition. Independent tread blocks with Torque-Locking sipes, wide circumferential grooves & W-shaped variable width lateral tread grooves help eject water from under the contact patch to resist hydroplaning & enhance wet traction.

Internally, the Pilot XGT Z4 radial's twin steel belts are reinforced using Michelin's B&ed At Zero (BAZ) technology (spiral-wrapped reinforcement) to stabilize the tread area, allowing it to withst& centrifugal forces at high speeds while minimizing tire weight & improving ride uniformity. The Pilot XGT Z4 radial features Michelin's Bead Tension Structure to blend performance with comfort. While all current sizes of Pilot XGT Z4 have been certified by Michelin to achieve a W-speed rating (168 mph maximum), some sizes are still br&ed as Z-speed rated (above 149 mph).

Out on our road test loop, the Michelin Pilot XGT Z4 delivered very crisp h&ling, making it a favorite around the twisty portions of the route. It did come with a penalty, however, as our team found the ride quality somewhat firm, feeling a bit harsh over the sharp expansion joints on the concrete expressway. Tread noise levels were appropriate for the category, but the loudest of the group in this test.

The crisp h&ling from the road carried over to the dry test track, where the Pilot XGT Z4 felt nimble & precise. This tire's responsive h&ling combined with a high level of overall grip to help the Pilot XGT Z4 post the fastest average overall lap time of the test.

Under wet conditions, the Pilot XGT Z4 did not feel quite as composed, however. Steering remained responsive when initially turning off center, but the overall grip level was just not able to match that of the other three tires in the test. Under acceleration, the rear drive axle of our BMW test cars broke loose easily as the vehicle accelerated around some of the tighter corners on our test track.